borders79

I’m looking at getting rid of my 17” rims (23lbs) and going to 16”, 13.5lb rota gt3’s with falken azenis.

Existing setup:
99 civic si. KYB G2 struts, H&R drop springs (1.8” front, 1.6” rear), korbach frame locks. Comptech front sway bar, DC sport rear lower tie bar. racing hart c5 evos 17” with kumbo 711’s

What changes, both good and bad, will I experience from doing this?
Handling, Acceleration, Breaking, Gas Mileage, Ride Comfort, Ride noise, Rubbing

Mike_C

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by borders79 &raquo;</TD></TR><TR><TD CLASS="quote">What changes, both good and bad, will I experience from doing this?</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by borders79 &raquo;</TD></TR><TR><TD CLASS="quote">Handling, Acceleration, Breaking, Gas Mileage, Ride Comfort, Ride noise, Rubbing</TD></TR></TABLE>

You answered your own question. 15s would suit you best, but to each his/her own.

borders79

Oh, I was asking, not listing what I expected to improve. I figured these things might change but I figured they won’t all be better. I’m just tired of how sluggish my car feels off the start. It is substantially worse than the stock si wheels at 18lbs.

accident prone

well first bonus is smaller radius spins faster, second your losing some wieght on the car generally basically, i agree with mike C on the 15s but i mean if you still like the larger wheel look go with the 16s, i prefer the 16 look on 99 coupes my slef since i have one with 15s and am upgrading to some light weight 16s in the near future, i would definetly switch over to the 16s personally

Mike_C

i believe the stock si wheels were 15lbs, but yes all of those things will improve. ride noise, comfort, and rubbing all depends on the tire selection, but you should see improvement assuming you get correctly sized ones.

CooBlueDAB

ok ok, ive heard this so many times but I still havent had these small questions answered.

Big rims = heavier... However, less rubber... Is the rubber lighter than the steel? because I always thought the rubber seemed much heavier than the rims of all my vehicles, even motorcycles.

Also... Say you have the stock SI rims at 15 inch, and a rim that is 17 inch, but the rubber makes the radius the same as the 15, ... ergo, gear ratios the same.... Then it should not make a difference in speed (unless rubber DOES make it lighter even if same diameter total wheel/tire), but maybe handling since it will be a stiffer tire... Good for road, not so much for really rough stuff though...

huntarrr

i would imagine that all tires weigh relatively the same, independently on the size. an 18" tire will have a smaller, yet thicker and stronger sidewall than a 15" tire would have. the difference in the weight between the tires shouldn't be much.

Mike_C

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CooBlueDAB &raquo;</TD></TR><TR><TD CLASS="quote">Big rims = heavier... However, less rubber... Is the rubber lighter than the steel? because I always thought the rubber seemed much heavier than the rims of all my vehicles, even motorcycles.</TD></TR></TABLE>

the metal is heavier... steel is nearly 8 times as dense as rubber, and aluminum is nearly 3 times as dense.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CooBlueDAB &raquo;</TD></TR><TR><TD CLASS="quote">Also... Say you have the stock SI rims at 15 inch, and a rim that is 17 inch, but the rubber makes the radius the same as the 15, ... ergo, gear ratios the same.... Then it should not make a difference in speed (unless rubber DOES make it lighter even if same diameter total wheel/tire), but maybe handling since it will be a stiffer tire... Good for road, not so much for really rough stuff though... </TD></TR></TABLE>

correct, however more often than not the outer diameters will not match up.

CooBlueDAB

Its true that it is more dense, but the rims done necessarily have the same amount of material in size as the tire, that is what I meant, and why I always felt that the rims were lighter... go figure....

However thank you both for actually answering these questions finally.

JinDIESEL

this is why i used to run 205/40/17 on 17" 5ZIGEN rims.. now, im about to run 205/50/15 on 15" rota's.... save weight, same diameter, same speed, same sht.

Mike_C

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JinDIESEL &raquo;</TD></TR><TR><TD CLASS="quote">this is why i used to run 205/40/17 on 17" 5ZIGEN rims.. now, im about to run 205/50/15 on 15" rota's.... save weight, same diameter, same speed, same sht.</TD></TR></TABLE>

are those really the same diameter? by my calculations the diameter of the 17" setup would be like half an inch larger.

borders79

So then what is ideal? Would you want the wheel/tire to be smaller in diameter than the stock setup? What size tires would I want to put on 16’s to match up the size with the stock 15’s?

Mike_C

smaller diameter = higher gearing (better accel, worse gas mileage)
larger diameter = lower gearing (slower accel, better gas mileage)

the size of the sidewall and the compliance of the rubber used will affect comfort and handling.

i really don't know squat about 16" tires, but assuming the si came with 195/50/15 (i think) a 205/40/16 would be your best bet to match the overall diameter, but that is a pretty thin sidewall.

dantastic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by borders79 &raquo;</TD></TR><TR><TD CLASS="quote">So then what is ideal? Would you want the wheel/tire to be smaller in diameter than the stock setup? What size tires would I want to put on 16’s to match up the size with the stock 15’s?</TD></TR></TABLE>

http://www.miata.net/garage/tirecalc.html


the 16" azenis size with the correct rolling diameter would be 215/45-16. the width may cause a bit of rubbing, but i've heard of people running fine with 'em with the proper offset

jDmImagE

I say Go with 15' rotas

willyboyK20

I just got those same wheels comming from si stocks on a 97 ex sedan with all the bolt ons and a lightwheight act flywheel. On both wheels i had the same rubber (falken ziex 512)

I when i put on the si stocks i did notice my acceleration had changed going from the stock steelies. It was a little slower and less peppier than before.

When i put the rota gt3's i didn't notice any slowdown, the peppyness surprisinly returned. I am very happy with my purchase.


p.s. To the poster above,The 99-00 Si's came with 195/55/15 tires. When going to 16's on a civic u want to go with a 45 series sidewall. (205/45/16.)

chad

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mike C &raquo;</TD></TR><TR><TD CLASS="quote">
15s would suit you best, but to each his/her own.</TD></TR></TABLE>

save even more weight and get 15's....15 inch tires are lighter too!!!

slammed_93_hatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mike C &raquo;</TD></TR><TR><TD CLASS="quote">
i really don't know squat about 16" tires, but assuming the si came with 195/50/15 (i think) a 205/40/16 would be your best bet to match the overall diameter, but that is a pretty thin sidewall.</TD></TR></TABLE>

SI's and most all honda's that have 15 inch wheels come with 195/55/15

00Red_SiR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mike C &raquo;</TD></TR><TR><TD CLASS="quote">smaller diameter = higher gearing (better accel, worse gas mileage)
larger diameter = lower gearing (slower accel, better gas mileage)
</TD></TR></TABLE>

Just to clarify this for everyone, when he said "higher" and "lower" he meant numerically ie: 3.78:1 gearing is numerically higher than a 2.78:1, but it is what we would refer to as lower gearing for faster acceleration etc... so a numerically higher ratio (lower gearing) will accelerate a car faster but reduce fuel economy and the opposite will happen with numerically lower ratio (taller gearing).

Mike_C

word... thanks for the two corrections/clarifications

borders79

I know the 15’s are ‘better’ for performance, but I really like the look of the 16’s and they are just a little heavier than the 15’s so I won’t be suffering too much.
At falken’s website they only offer azenis in 215/45/16, They do not have 205/45/16. I was thinking that was the ideal size for 16’s. Am I missing something here?
Anyone know the weight of the rota 16” GT3’s? I’ve read 13.5 and 16.5. What is it?

willyboyK20

with the azeins they don't make them in 205 width for 16's hell their 15 inch 205 width is more like 215

I have the ziex brand which they do make in 205's. U can get away with the 215's on your si because the 96-00 civics wheel wells are bigger than the 92-95. It really depends on how much u are lowered.

borders79

1.8” front 1.6” in rear. I rub a little now with my 17’s, but only when I have a passenger and turn hard. My 17’s have 205’s. Would it be worse with 215?
So I understand that having lighter wheels will make my gas mileage worse? It looks like it’d make it better because it takes less energy to get the wheels turning.

Mike_C

there are so many factors that go in to gas mileage, i feel stupid for even bringing it up.

if the tire/wheel combos were the same exact weight, the larger diameter would get better mileage, because it require less rpm to move an equal distance.

given that the smaller combo will weigh less, this difference is reduced... to what extent? i don't know.

borders79

Theory time. Would dyno numbers change with smaller tires? Would the less weight wheels allow more power to get from the crank to the ground? Or would it just FEEL faster?